get random strings for use in testing

TestUtil.cs

   public static class TestUtil
   {
      private static Random _random = new Random();

      public static string MakeRandomString(int numchars = 8)
      {
         const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";
         return new string(Enumerable.Repeat(chars, numchars).Select(x => x[_random.Next(x.Length)]).ToArray());
      }

      public static string MakeRandomWordString(int numwords = 4)
      {
         string[] words = { "Alpha", "Bravo", "Charlie", "Delta", "Echo", "Foxtrot", "Golf", "Hotel", "India", "Juliet", "Kilo", "Lima", "Mike", 
                            "November", "Oscar", "Papa", "Quebec", "Romeo", "Sierra", "Tango", "Uniform", "Victor", "Whiskey", "X-ray", "Yankee", "Zulu" };

         var sb = new StringBuilder();

         for (int i = 0; i < numwords; i++)
         {
            sb.Append(words[_random.Next(words.Length)] + " ");
         }
         return sb.ToString().Trim();
      }

   }